Biological wastewater purification device

ABSTRACT

Biological purification device with a multi-chamber tank with separating walls to divide the tank into at least one pretreatment chamber containing activated sludge and at least one purification chamber, as well as pump installations ( 14, 44 ) for transporting and treating wastewater, includes a distributor ( 16, 18, 20; 46, 56, 60 ) for dividing the a pump output into at least one main flow and at least one secondary flow and which is connected downstream of at least one pump installation ( 14, 44 ).

The invention concerns a biological wastewater purification device with a multi-chamber tank with separating walls to divide the tank into at least one pre-treatment chamber containing activated sludge and at least one purification chamber, as well as pump installations for transporting and treating wastewater.

As a general rule, small wastewater treatment systems contain a plurality of pumps such as a clear water removal pump, a sludge pump, a ventilator, etc. Additional pumps may also be provided to transport and treat, e.g. aerate, the wastewater during the purification process.

A large number of pumps not only leads to substantial costs for the pumps themselves, but also to additional expenditure for cabling and controlling the pumps. This makes the systems more expensive more complicated and more susceptible to wear and tear.

This invention is therefore based on the task of creating a wastewater purification device of the above-mentioned type, which requires less equipment-related expenditure.

In order to solve this task, the wastewater purification device according to the invention is characterised in that a distributor for dividing the pump output into at least one main flow and at least one secondary flow is connected downstream of at least one pump installation.

This implies the use of a pump capable of performing two functions. One pump and related accessories can be dispensed with. The distributor is preferably configured to permit relatively accurate dosing, especially of the secondary flow. Under these circumstances, the invention can be used in such a way that, for example, the operation to return the sludge to the pre-treatment chamber, which need only take place from time to time and with relatively small quantities of water and sludge, is performed by the secondary flow.

Sludge return is an operation used in activated sludge wastewater purification processes to supply the fresh wastewater flowing into the sedimentation chamber or pre-treatment chamber with sludge in which micro-organisms have already formed.

The dosing of the secondary flow can be achieved in different ways. Valves may be provided, which, for example, let through a certain limited volume of water at the start or end of the pumping operation.

By way of the main task, the pump according to this invention can, for example, pump the water in the purification chamber through a Venturi aerator. Other pump tasks are also feasible.

A suitable valve providing a simple means of allowing a dosed, relatively small volume of water to flow into the secondary line, comprises, for example, a valve ball positioned so that it can move between two valve seats in a rising section of the secondary line. When the pump is switched on, the valve ball is lifted off the bottom seat and carried upwards with the flow of water towards the top valve seat. During this time, water can flow past the valve ball into the secondary line until the ball comes into contact with the top valve seat, where it is held fast by the pressure of the rising water. If the pump is turned off, the ball will sink back down onto the bottom valve seat. Hence this is a solution allowing a limited, dosed quantity of water to flow into the secondary line at the start of the pumping operation.

A valve of this type can be supplemented by an upstream or downstream non-return valve.

Another embodiment of a suitable valve might comprise a valve ball which can move to and fro between two valve seats located at an outlet line of the pump on the one hand and the secondary line on the other hand, and which has a water reservoir in a rising section of the main line. If the pump is switched on, the ball is lifted upwards towards the valve seat on the secondary line, and the secondary line is closed off.

The water flows into the main line and then into the water reservoir. If the pump is switched off, the ball falls back onto the valve seat on the outlet line of the pump. The water collected in the water reservoir flows back into the secondary line, which is now open.

These valve types merely serve as examples of numerous other possibilities.

Preferred examples of embodiments of the invention will be described in more detail below with reference to the enclosed drawings, in which

FIGS. 1 a and 1 b show a first embodiment of a valve envisaged for the secondary line in accordance with the invention, in different operating positions;

FIG. 2 a to 2 c show an equivalent view of a second embodiment of a valve;

FIG. 3 a to 3 e show a third embodiment of a valve according to the invention;

FIGS. 4 a and 4 b show a fourth embodiment of a valve.

FIG. 1 a is a diagrammatic representation of a purification chamber 10 containing more or less purified water up to water level 12. Inside purification chamber 10 there is a pump 14 from which proceeds a pump outlet line 16 which immediately branches into a main line 18 and a secondary line 20. In the example shown, the main line feeds into a Venturi aerator 22 and an air line 24 intersects with the narrow portion of said Venturi aerator.

In a rising section of secondary line 20 there are two valve seats 26,28 facing each other at a distance, between which a ball 30 can be moved up and down.

When pump 14 is switched on, valve ball 30 is gradually lifted off the bottom valve seat 26 until it comes into contact with top valve seat 28. As the ball rises, water flows past the ball and through secondary line 20. This water flow stops as soon as the ball comes into contact with the upper valve seat 28. It is held in this position by the pressure of the water for as long as pump 14 stays in operation. When pump 14 is switched off, valve ball 30 sinks back down onto the bottom valve seat 26.

This process is repeated the next time the pump is switched on. This provides a means of occasionally pumping limited volumes of sludge-containing water back into the pre-treatment chamber (not shown) via secondary line 20 without the need for a separate pump.

FIG. 2 a to 2 c show another embodiment of the invention. This embodiment is based on the embodiment of FIGS. 1 a and 1 b, but also includes a non-return valve in addition. The same reference numerals have been assigned to components already mentioned in the context of FIG. 1. FIG. 2 a to 2 c also provide for the same valve ball 30 as shown in FIG. 1, which can be displaced between bottom valve seat 26 and top valve seat 28 in the manner already described.

Downstream of the arrangement comprising valve ball 30 with the two valve seats 26,28 there is a non-return valve 32. In the case illustrated, the non-return valve is contrived as a ball valve. It comprises a valve ball 34, which, in the upstream direction, can rest against a valve seat 36, thereby preventing a return flow. Valve ball 34 is located inside a slightly broadened chamber 38, in which a ball support 40 is disposed, against which the ball rests when the non-return valve is opened (FIG. 2 c).

The way in which this valve functions will be described below.

FIG. 2 a shows the position in which pump 14 is switched off. When pump 14 is switched on (FIG. 2 b), valve ball 30 is gradually lifted upwards. As already mentioned, there is only a small gap between valve ball 30 and the walls of the secondary line, so water can rise up past valve ball 30.

This flow of water lifts valve ball 34 of non-return valve 32 up off its valve seat 36 and presses the ball against support 40. When valve ball 30 comes into contact with the top valve seat 28 (FIG. 2 c), the flow of rising water is interrupted. Valve ball 34 of the non-return valve 32 sinks back down onto its valve seat 36.

FIG. 3 a to 3 e are equivalent to FIG. 2 a to 2 c, except that in FIG. 3 a to 3 e, the non-return valve is disposed before or upstream of valve ball 30 with the two valve seats 26,28. As the figures coincide fully in all other respects, the same reference numerals will be used as in FIG. 2 a to 2 c and, to some extent, in FIGS. 1 a and 1 b.

The way in which the embodiment of FIG. 3 a to 3 e functions will now be described below.

FIG. 3 a shows the position in which the pump is switched off. If pump 14 is switched on, valve ball 34 of non-return valve 32 is first lifted off its valve seat 36 (FIG. 3 b). The flow of water can now enter secondary line 20 so that valve ball 30 is lifted up from its bottom valve seat 26 to its top valve seat 28. Water flows through secondary line 20 during this time. As soon as valve ball 30 reaches the top valve seat 28 (FIG. 3 c), the flow of water in secondary line 20 is interrupted. Valve ball 34 of non-return valve 32 therefore sinks back down onto its valve seat 36 (FIG. 3 d). When the pump is switched off, valve ball 30 also sinks back down onto its bottom valve seat 26 (FIG. 3 e).

FIGS. 4 a and 4 b show an arrangement which functions according to a different principle than the embodiments described thus far. In a purification chamber 42 there is a pump 44 from which a pump outlet line 46 proceeds in a vertical direction.

Adjoining a bottom, non-designated first section of pump outlet line 26, the latter runs into a broadened section 48, and at the transition between the bottom section and the top, broadened section 48 there is a valve seat 50, on which a valve ball 52 is seen resting in FIG. 4 a. Disposed concentrically inside this broadened section 48 is inlet 54 of the secondary line 56, which is equivalent in terms of the way it functions to the secondary line 20 of FIG. 1.

There is a valve seat 58 at this inlet 54 of secondary line 56. This valve seat 58 lies directly opposite bottom valve seat 50 and is disposed coaxially to the latter.

The main line 60, which corresponds to the main line 18 of the previously described embodiments, branches off from the broadened section 48 of pump outlet line 46 of the embodiment according to FIGS. 4 a and 4 b. Main line 60 has a water reservoir 62 in a rising section adjoining the broadened section 48 of pump outlet line 46.

The way in which the embodiment of FIGS. 4 a and 4 b functions will now be described below.

FIG. 4 a shows the position in which pump 44 is switched off. Valve ball 52 rests against its valve seat 50. When pump 44 is switched on, valve ball 52 is lifted upwards from bottom valve seat 50 towards valve seat 58 at the inlet of secondary line 56. This seals off secondary line 56. The water flows through the main line 60. If pump 44 is now switched off, valve ball 52 sinks back down to its bottom valve seat 50. Hence this arrangement operates as a non-return valve. The water collected in the water reservoir 62 cannot run off via the main line because of the heights involved and therefore flows back into the broadened section 48 of the pump outlet line and from here through secondary line 56. At this point it should be pointed out that FIGS. 4 a and 4 b in particular are merely diagrammatic illustrations. It is obvious that the volume of water reservoir 62 and of the broadened section 48, and the arrangement and dimensions of secondary line 56 must be chosen so that a given volume of water can flow away via secondary line 56. 

1. Biological purification device comprising: a multi-chamber tank with separating walls to divide the tank into at least one pre-treatment chamber containing activated sludge and at least one purification chamber, at least one pump installation for transporting and treating wastewater, and a distributor for dividing a pump output into at least one main flow and at least one secondary flow, the distributor connected downstream of said at least one pump installation.
 2. The purification device of claim 1, wherein the distributor comprises a main line and a secondary line which proceed from a pump outline line.
 3. The purification device of claim 1, wherein the distributor comprises, in the secondary line, at least one of: a butterfly valve arrangement and a ball valve arrangement.
 4. The purification device of claim 3, wherein the at least one of the butterfly and ball valve arrangement is provided in a rising section of the secondary line and comprises a valve ball which can be moved up and down between two valve seats.
 5. The purification device of claim 4, further comprising a non-return valve disposed upstream of the valve arrangement comprising the valve seats and the valve ball in the secondary line.
 6. The purification device of claim 4, further comprising a non-return valve disposed downstream of the valve arrangement comprising the valve seats and the valve ball in the secondary line.
 7. The purification device of claim 1, wherein the distributor comprises a main line and a secondary line, and a water reservoir in a raised position of the main line, such that water in the water reservoir flows back and into the secondary line when the at least one pump installation is switched off.
 8. The purification device of claim 7, wherein the distributor further comprises a valve ball which can be moved between a first valve seat at a pump outlet line and a second valve seat at an inlet of the secondary line which, when the at least one sums installation is switched on, is lifted up from first valve seat at an end of the pump outlet line and pressed by the flow of water against the second valve seat at the inlet of the secondary line, but when the at least one pump installation is switched off, sinks back onto the first valve seat at the end of pump outline line, thereby opening the inlet to the secondary line.
 9. The purification device of claim 8, an inlet area of the secondary line lies concentrically inside a broadened section of the pump outlet line. 